-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to Bruno Haible on 10/23/2008 5:09 PM: > There is a need for autoconf macros to compile and execute programs that > they have created with AC_LANG_CONFTEST > 1) without having to build up the compile or link command by itself, > 2) with log of the command and its error messages and exit code to the log > file. Yes, but it probably should not be named AC_TRY_EVAL, so that existing uses of the undocumented and broken interface aren't themselves broken when we close the security hole in whatever we document. In particular, AC_TRY_EVAL is an undocumented interface which, in the autoconf sources itself, mentions that it is unsafe and may be withdrawn or changed in the future. > > ac_gcj_link="$GCJ $GCJFLAGS conftest.java --main=conftest -o conftest$ac_exeext" > AC_TRY_EVAL([ac_gcj_link]) It sounds like we need to add a public wrapper around _AC_DO_VAR and _AC_DO_TOKENS, as those are the safe replacements for the broken AC_TRY_EVAL. > > In libtool you find many uses of > > AC_TRY_EVAL(ac_compile) > and > AC_TRY_EVAL(ac_link) > > but also two more complicated ones: > > AC_TRY_EVAL(NM conftest.$ac_objext \| $lt_cv_sys_global_symbol_pipe \> $nlist) > AC_TRY_EVAL(_LT_TAGVAR(archive_cmds, $1) 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1) Right now, I think a close start for the alternative would be some wrapper around: _AC_DO_TOKENS([$NM conftest.$ac_objext \| $lt_cv_sys_global_symbol_pipe \> $nlist]) _AC_DO_TOKENS(_LT_TAGVAR(archive_cmds, $1) [2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1]) > > So, not only AC_TRY_EVAL should be documented, but also the variables 'ac_link' > and 'ac_compile'. Better than documenting variables would be designing a nicer macro interface that exposes what those variables are trying to get at. Every time we document a shell variable instead of an autoconf macro, we've locked ourself into a particular implementation, instead of hiding behind a stable API where we can tune for performance. - -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@xxxxxxx -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkkBL8YACgkQ84KuGfSFAYCi1wCgwka0Zrx9t2UinrAc9QJZ+93r u84AoI1fn7Qlv3gYVoCutIAtvgev/6x6 =qukv -----END PGP SIGNATURE----- _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
